>>1103Something goes wrong with the last or first frame when this banner comes up.

If I had to guess, I'd say it's the same problem kusaba seems to have with thumbnailing optimized gifs. You can see a little distortion in the thumbnail here, then a different kind of error when this banner comes up in the rotation. Somehow automated optimization breaks kusaba's handling of graphics interchange format.

pic related, unoptimized with gimp and cut "7chan" out of all but the background layer. does this work better?